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28 / Health Issues Caused by Obesity
properly use the insulin it does make (this is called insulin resistance). Most
people with type 2 diabetes are insulin resistant, so we’ll focus here. What
does “insulin resistant” mean?
When we eat carbohydrates (foods such as cereal, fruit, starchy vegeta-
bles, pasta, rice, bread, cookies, or muffins), our bodies convert the food into
blood sugar (glucose) to give us the energy we need to maintain life. Our
blood carries this glucose to all the cells in our body (fat, muscle, and organ
cells). Insulin, produced by beta cells in the pancreas, is the hormone that
lets that glucose into our cells. Insulin acts much like a key, unlocking cells to
let in the glucose.
Once glucose enters a cell, that cell has three options for how to use it: it
can immediately use the glucose for energy; it can store the glucose form
called glycogen for use in the near future; or it can convert the glucose into
fat for long-term energy storage. As cells take in the glucose, overall glucose
levels in the blood drop, signaling the pancreas to stop making insulin.
(Otherwise cells would keep letting in more blood sugar and deplete
blood-glucose levels to an unhealthy low, a condition called hypoglycemia.)